(CF{11 ){11 {11 CFO{116 Ag{115

ABSTRACT

This invention relates to novel salts which are prepared by the reaction of a fluorine-containing perhalogenated ketone with a compound selected from the group consisting of potassium fluoride, silver fluoride, cesium fluoride, rubidium fluoride and tetraalkylammonium fluoride. These salts are useful for the preparation of fluorinated ethers which can be employed in the preparation of surfactants.

United States Patent [1 1 Litt et al.

1 1 Sept. 11,1973

[ (CF3)2 CFO-AG [75] Inventors: Morton H. Litt; Francis W. Evans,

both of Morristown, NJ.

[73] Assignee: Allied Chemical Corporation, New

York, N.Y,

[22] Filed: Sept. 3, 1968 [21] Appl. No.: 778,887

Related US. Application Data [62] Division of Ser. No. 492,276, Oct. 1,1965, Pat. No.

3,358,033 12/1967 Anello et al. 260/633 X 3,382,222 5/1968 Pittman etal.... 260/633 UX 3,384,628 5/1968 Pittman et al 260/633 UX OTHERPUBLICATIONS Redwood et al., Canadian J. of Chem. Vol. 43, Pg. 1893(July 1965) Primary ExaminerI-lelen M. S. Sneed Att0rneyArthur J.Plantamura [57] ABSTRACT This invention relates to novel salts which areprepared by the reaction of a fluorine-containing perhalogenated ketonewith a compound selected from the group consisting of potassiumfluoride, silver fluoride, cesium fluoride, rubidium fluoride andtetraalkylammonium fluoride. These salts are useful for the preparationof fluorinated ethers which can be employed in the preparation ofsurfactants. 1

1 Claim, No Drawings Heretofore perfluorinated aliphatic ethers havebeen prepared by electrolyzing the corresponding dialkyl ethers inhydrogen fluoride. These perfluorinated ethers have a high degree ofchemical inertness and, thus, it is extremely difficult to use them asintermediates in the preparation of other compounds. This chemicalinertness results from the strong carbon-to-fluorine bond. More reactivecompounds can be produced by replacing at least one of the fluorineatoms of the above-described perfluorinated ethers with a differenthalogen to thereby provide a more active site. Additionally, a widerrange of properties can be obtained if the process for producing thefluorinated ether is such that hydrogen or other substituents canbeplaced in selected positions. 7

It is, therefore, an object of the present invention to providefluorine-containing ethers which are useful as intermediates in thepreparation of other compounds.

Another object of this invention is to provide fluorine-containingethers in which at least one substituent is a member of the groupconsisting of chlorine, bromine or iodine.

A further object of this invention is to provide a process for thepreparation of the above-described ethers.

Additional objects and advantages of this invention will be apparentfrom the following detailed description thereof.

The fluorine-containing ethers of the present invention are representedby the formula wherein R and R are independently either fluorine or aperhalogenated alkyl radical in which the halogen atoms are selectedfrom the group consisting of fluorine and chlorine with at least onefluorine atombeing 40 where R, and R, are independently selected fromthe group consisting of chlorine, hydrogen and alkyl of one to 10 carbonatoms; Y is selected from the group consisting of chlorine, bromine andiodineiR, and R, are independently selected from the group consisting offluorine and hydrogen; R is selected from the group consisting offluorine, hydrogen, chlorine, bromine, idine, and perfluorinated alkylof one to 16 carbon atoms with R always being fluorine when both R andR, are fluorine; and p is an integer of l to 9.

These ethers are preferably prepared by first reacting a perhalogenatedketone or a perhalogenated acyl fluoride with an ionizable fluoride saltto form a fluorinated organic salt and then reacting the organic saltswith an olefin and a halogen other than fluorine (chlorine, bromine,iodine and diatomic interhalogens thereof such as iodine monochloride)to form the desired ether. The first reaction is illustrated by thefollowing equation:

(I) R 5 n-o-w-o MF nix-o-w where R and R have the meanings given above,and M is a member selected from the group consisting of potassium,cesium, silver, rubidium, and tetraalkylammonium ions.

The olefin reacted with the fluorinated organic salt in the secondreaction is selected from the group consisting of compounds of thefollowing formulas:

l. R,CH=CHR, where R, and R, have the meanings given above;

2. R,CF=CR,R,, where R R, and R have the meanings given above; and

(3) ICHI-CH,

dH irmp where p has the meaning given above.

The reactions of the above olefins and a halogen with the fluorinatedorganic salts are illustrated by the following equations:

' Fc0-M+ R1CH=CHR Y,

R R1 R1 FiJ-O-JJH-JJHY MY When a perhalogenated acyl fluoride,

e.g., a com- I pound of the formula:

Exami i i F where X is fluorine or chlorine with at least one fluoand nhave the meanings given above. On the other hand, when a perhalogenatedketone, e.g., a compound 7 of the formula:

m 2m+l m'Xim'H where m and m are preferably integers of 1 to 8' with thesum of m and m preferably not exceeding 10, and X is fluorine orchlorine with at least one X on each carbon atom being fluorine, isemployed as astarting material, an ether is produced in which both R andR' area perhalogenated alkyl radical. Such ethers are illustrated bytheformula:

halogenated ketones or perhalogenated acid fluorides and a fluorinatedcompound of the formula MF to form a fluorinated organic salt proceedsreadily upon admixture of the reactants and can be conveniently carriedout at room temperature. A suitable procedure is to add the fluorinatedketone or acyl fluoride to a suspension of the MP salt ina liquid mediumwhich is a solvent or partial solvent for the desired product. Suitableliquid media which can be used are lower alkyl nitriles such asacetonitrile, lower alkyl t-amides such as dimethyl formamide,nitrobenzene, butyrolactone, sulfolanes such as Z-methyl sulfolane, andsulfones such as methyl ethyl sulfone. As the size of ketone oracidfluoride molecule increases, the fluorinated organic salt producedbecomes less soluble and the yield of product 'islowered. It istherefore preferred touse ketones' and acid fluorides containing ll orless carbon atoms, although larger molecules can be used ifdesired.

Preferably about 0.8 to 4 mols of the fluoride salt MP is used for eachmol of fluorinated ketone or acyl fluoride. The organic salt produced isdecomposed by water,'and it is therefore recommended that the reactionbe conducted under anhydrous conditions. Since tetraalkyl ammoniumfluorides are somewhat unstable and difficult to handle, the tetraalkylammonium salts are preferably prepared by first making a potassium saltin accordance with Equation (1) and then reacting the potassium saltwith either a tetraalkyl ammonium chloride or a tetraalkyl ammoniumperchlorate to form the desired product and a KCl or KClt) precipitate.

Suitable ketones for use in the present invention includehexafluoroacetone; a-chloropentafluoroacetone;01,01-dichlorotetrafluoroacetone; a,a,a'-trichlorotrifluoroacetone;tux-dichlorotetrafluoroacetone; octafluorobutanone;oz-chloroheptafluorobutanone; decafluoro-3 -pentanone;2-trifluoromethyl-3- perfluoropentanone; dodecafluoro-B-hexanone;

tetradecafluoro-3-heptanone; perfluoro-6- undecanone, etc. Suitable acylfluorides include trifluoroacetyl fluoride; carbonyl fluoride;chlorodifluoroacetyl fluoride; pentafluoropropionyl fluoride;

B-chlorotetrafluoropropionyl fluoride; heptafluorobu- "tyryl fluoride;nonofluoropentanoyl fluoride; undeca- -fluorohexanoyl fluoride;tridecafluoroheptanoyl fluocanbe conveniently conducted inthe sameliquid mediumas the first reaction, and it is unnecessary to isolate thefluorinated organic salt formed in the first reaction, but rather theolefin and halogen reactants can be added directly to the reactionmixture. The general formulas of the three groups of oleflns which canbe-employed in the present invention are given above. Illustrative ofspecific olefins are: CH,=Cl-l CF =CF,,

The fluorinated ethers can be separated from the other compounds presentin the reaction mixture by fractional distillation. lf excess iodineispresent, the purification of the fluorinated ether is facilitated ifthe excess iodine is first converted to Nal by reaction with an equeoussolution of sodium sulfite prior to the fractional distillation.

A particularly outstanding group of compounds within the scope of thisinvention are those fluorinated ethers prepared from perhalogenatedacetones containing at least three fluorine atoms. The ethers thusprepared possess terminal perhalogenated iospropyl radicals and can beconverted to excellent surfactants by a process hereinafter described.These ethers are represented by the formula:

chlowherein R"MgX'represents a Grignard reagent in which X is a halogen.The reactions involving the Grignard reagent and the carbon dioxideproceed very rapidly and can be conducted at temperatures considerablybelow 0 C. It is recommended that both of these reactions be conductedat temperatures below'0 C. in order to better control the reaction ratesand prevent decomposition of the Grignard reagent. The fluorinated acidsand the alkali metal salts thereof lower the surface tension of waterand thus are useful as surfactants. The fluorinated acids and alkalimetal salts prepared from perhalogenated ketones are novel compounds.

Those ethers having the formulas:

wherein R, R, R R R R and Y have the meanings given above, can betreated to remove hydrogen and halogen, thereby forming vinyl ethers.This dehydrohalogenation can be accomplished by treatment with a strongbase. In a typical procedure, 100 grams of the above ether are admixedwith 80 grams of NaOl-I and 80 grams of soda lime and the reactionmixture is distilled, the distillate thus obtained being the desiredvinyl ether.

The following examples are given to further illustrate the invention,but it is to be understood that the invention is not to be limited inany way by the details described therein.

EXAMPLE 1 Into a flask equipped with a dry-ice" condenser and a magneticstirrer were placed 26 grams of anhydrous potassium fluoride and 200milliliters of acetonitrile. The resulting suspension was stirred, and82 grams of gaseous hexafluoroacetone were added over a 1-hour period,during which time the temperature of the reaction mixture rose from 24to 42 C. Stirring of the reaction mixture was then continued for anadditional 2 hours, after which almost all of the potassium fluoride haddissolved. The reaction mixture was admixed with l.liter of dry benzeneand cooled, thereby'precipitating 91.62 grams of an organicsalt whichwas recovered by filtration. This organic salt was determined to be(CF,,),FCO'K with a small amount of KF being ad- 6 mixed therewith.Analysis: Calculated; C, 16.07596; K, 17.445%. Found; C, 14.5%, K,20.0%.

EXAMPLE 2 In a flask equipped with a dry-ice condenser and a mechanicalstirrer was placed 7.2 grams of potassium fluoride and 77 cc. ofacetonitrile. The resulting suspension was stirred and 23 grams ofgaseous hexafluoroacetone added over a 20-minute period, during whichtime the temperature of the reaction mixture rose from to 435 C. Asolution of 28.6 grams of tetraethylammonium perchlorate dissolved in 110 cc. of acetonitrile was added to the reaction mixture resulting inthe precipitation of KClO which was removed by filtration. The filtratewas poured into 1 liter of benzene, thereby precipitating 11.4 grams ofan organic salt of the formula (CF ),FCO (C H,CH,),N which was recoveredby filtration.

EXAMPLE 3 A series of experiments were carried out in which organicsalts of perhalogenated acetones were prepared in a manner similar tothat described in Example 1, but, instead of precipitating the organicsalts by adding the reaction mixture to benzene, fluorinated ethers wereprepared by adding an olefin and a halogen to the reaction mixture. Atypical example is as follows:

In a flask equipped with a dry-ice" condenser and a magnetic stirrer wasplaced 1.0 liters of acetonitrile and 116 grams of anhydrous potassiumfluoride. 'The resulting suspension was stirred and 166 grams ofhexafluoroacetone was added over a l-hour period during which time mostof the KF dissolved. Two-hundred and fifty-four grams of iodine wasadded and then 39 liters of tetrafluoroethylene was added over a periodof 5.5 hours with the temperature of the reaction mixture being about 26C. The reaction mixture was stirred for an additional 15 hours and thenpoured into 1 liter of ice water. A solution of sodium sulfite was addeduntil all the iodine was reduced and the solution became colorless. Thereaction mixture was then diluted with 4 liters of water, followingwhich the organicliquid was separated. The organic liquid wasfractionally. distilled to give a 17 percent yield ofperfluoroisopropyl,2- iodotetrafluoroethyl ether having a boiling pointof 8687 C./760 mm. Hg. and a refractive index at 25 C. of 1.3155.Analysis: Calculated; C, 14.6%; I, 30.8%. Found: C, 14.7%; I, 30.2%.

The same fluorinated ether was produced by repeating the aboveprocedure, substituting silver fluoride for the potassium fluoride.Theorganic salt intermediate formed in this reaction was:

1 A number of different fluorinated ethers were prepared using the aboveprocedure but substituting approximately equivalent molar proportions ofother reactants. When the halogen compound added in the second' stepcontained chlorine or bromine, the halogen was added slowly at the sametime the olefin was added and the purification of the fluorinated etherwas changed slightly. Potassium iodide was added to the reactionproductto convert the remaining chlorine or TABLE I-Continued First reactantsSecond reactants Fluo- Organic salt Halo- Fluorinated'ether RefractiveB.P. of product, Ketone ride intermediate Olefin gen product and yieldindex of product CJmm. Hg

KF 0K+ CF2= CF. is cmo-crzcrzsr 1.2so 21 c- "ins sts/760mm. II I Yield:28%. CFaC-CF3 CFa-(fi-CFB Isomeric mixture (I? KF 0-K+ CH2= CHCl 13 (a)(3150101121 1.3925/24 C 51-52/25 mm.

e C Fs-CC F3 0 Fg--C F3 (b) C F1OCHZCHCII I Yield: 9.1%.

H KF O"K CHCH2 1C1 lI 1.4214/22 C 49-49.!5/5 mm.

Fz-CCF; CFa-l-CFa CH CH2 (DH-CH2 1 I F CHr-CHz CaFCH /CH2 CHz-CHZ Yield:42%.

O CSF O-CS CH2= CH2 Brz CsF70-CHzCHzBI 0 38-9U/750 111ml6 Yield: 17%. CF-CF CFa -CFs (i) KF 0K+ CH CHCgH Brg C F O CHCH Br 1.4087I23 C- 5961/1mm. CFa-(C F3 CFz---C Fa 2H" 1 Yield: 5%. F

TABLE II Percent chlorine or Percent carbon Percent hydrogen Percentfluorine Percent iodine bromine Compound Found Cale. Found Cale. FoundCale. Found Cale. Found Cale.

aFrO CFZCFZI 14. 7 14'. s so. 2 CaFrO CFgCHzI 15. 96 15. 96 0. 42 0. 5643. 0 45. 5 34. 3 CsF1OCFHCHzI l6. 8 16. 8 0. 81 0. 84 41. 0 42. 4 34. 8CaFrOCHzCHzI. 17. 5 l7. 6 1.32 l. 39. 5 39. 1 87. 3

a 1OCFr(]3FI 16.1 15.6 49.0 53.5 26.8

CaF1OCF2CFOlL" 13.9 14. 0 CaFvOCFzOFBrI. 13. 1 12. 7 CaFuCIOCFzOFzI. 13.7 14. 0 C11FC12O CFQCFZI 13.7 13. 5 CaF4 C130 CFZCFQI 13. 4 13. 0CsF1OCFzCH2Br. 18. 15 18. 2 CaF1OCFHCHzBr 19. 3 19. 3 CaF7OCF2CH2C1-..21.5 21. 1

' rsoms'rnic MIXTURE (a) C3F1OCHCH2B1 CaF70CH2CHBr C a zo FzcFzBr 1e. 416. 4 19.7 (Br) 21. 9

15014131110 MIXTURE (a) 03110o11c1d11.1 16.3 16.0 0.96 0.80 as. s 38. 911.5 (C1) 5 (b) CZIF'IQCHZCIICIII i 27. 2 21. 4 2.80 2. 5s a2. 1 32. 2

a 1O cmclmsr 20. 9 20.5 1. 74 1. 4o 3 a 1 OIlCIIz'Br 37.8 38.5 5.13 asaHn EXAMPLE 4 Into a flask equipped with dry-ice condenser and a stirrerwas placed 250 ml. of acetonitrile and 76 grams.

of cesium fluoride. The resulting suspension was stirred and 41 grams ofperfluoropropionyl fluoride was added over a l-hour period. During thisaddition, the heat of reaction caused the temperature to riseto C. and

the flask was then cooled with ice for the remainder of EXAMPLE In aflask equipped with a dry-ice condenser and a stirrer was placed 250 ml.of acetonitrile and 15 grams of potassium fluoride. The resultingsuspension was stirred and 45 grams of perfluoropropionyl chloride wereadded over a 1-hour period. After the addition of grams of theperfluoropropionyl chloride, a 40-gram charge of cesium fluoride wasadded to the reaction;

mixture. During the reaction, the temperature of the reaction mixturerose from 24 to 40 C. at which time the flask was cooled with coldwater.

The resulting solution was saturated with ethylene. A

solution of 40 grams of bromine in 250 ml. of ac etoriitrile and 28liters of gaseous ethylene were then simulta- 12 in accordance with ASTMTest D-l590. The results were as follows:

Concentration of Fluorinated Salt Surface Tension in Water (Wt.(Dynes/cm.) 0 73.0 0.14 57.2 0.27 44.0 0.53 37.0 1.25 34.6 2.30 29.63.70 23.0 5.50 22.6

The corresponding acid was prepared by acidifying the' above sodiumsaltwith HCl to a pH of 1.5. The effect of this acid on the surfacetension of water was tested and the results were as follows:

neously added over a 7-hour period. The resulting" product was poured inice water and a solution of 2.49 grams of Na SO in 12 cc. of .water wasadded. The organic layer was separated and fractionally distilled togive a 17 percent yield of perfluoropropyl, 2brorno-' ethyl ether havinga refractive index of 1.3458/24 C. and a boiling point of 88'90 C./760mm. Hg. Analysis: Calculated C, 20.5%; H, 1.40%; Br, 27.3%; Found C,20.9%; H, 1.74%; Br, 29.9%. 1

EXAMPLE 6 In a flask equipped with a dry-ice condenser and a magneticstirrer was added 21.6 grams of b'romoben' zene, 3.35 grams ofmagnesium, and 150 ml. of anhydrous ethyl ether, and a Gri'gnard reagentwas prepared in the standard manner under a nitrogen atmosphere. Thereaction flask was cooled with dry ice and an additional 50 ml. ofanhydrous ethyl ether were added. A solution of 51.5 grams ofperfluoroisopropyl, 2-iodotetrafluoroethyl ether and 50 ml. of ethylether was added to the reaction mixture which was then stirred forone-half hour. Another 100 ml. of ethyl ether was added and the reactionmixture allowed to warm to'42 C. Carbon dioxide was bubbled into thereaction mixture at a rate of 0.1 mols per hour for 2 hours. Stirringwas then continued for 16 hours while allowing the reaction mixture towarm to room temperature.

The reaction mixture was next cooled to 0 C. and 400 ml. of precooled 24percent sulfuric acid was added. The ether layer was separated and theaqueous layer extracted three times with 100-ml. portions of ethylether. The ether solutions were combined and a product consistingprimarily of (CF ),FCOCF,CF- ,COOH was obtained by fractionaldistillation. The product was dissolved, in absolute methyl alcohol andtitrated with a solution of 2N sodium hydroxide in methyl alcohol to aphenolphthalein end point,v The solution was flash evaporated underreduced pressureto dryness, yielding 9.1 grams of o cmnscoc'mc 1 ,04

ONa

The effect of this composition on the surface tension of water wasdetermined by measuring the surface tensions of a series of aqueoussolutions with a tensiometer Concentration of Fluorinated Acid in Water(Wt.

Surface Tension (Dynes/cm.)

EXAMPLE 7 A suspension of 2.6 grams of magnesium in 1,000 cc. of ethylether was placed in a flask'equipped with a dry ice condenser and amagnetic stirrer, and 20 cc. of bromoben'zene was added to form theGrignard reagent C H MgBr. The reaction mixture was cooled to 75 C. withdryice and nitrogen was bubbled through the solution to'r'ernove all theoxygen. A solution of 45 grams of l ,3 dichloropentafluoroisopropyl,2'iodotetrafluoroethyl ether in 50 ml. of ethyl ether was added to thereaction mixture with stirring over a period of15 minutes. The reactionmixture was allowed to warm to '40 C. and carbon dioxide was passedthrough the reaction mixture for 2 'hours at a rate 'of 0.1 mols perhour. The reaction mixture was warmed to room temperature and then flashevaporated to remove the ether solvent. The residue was washed withhexane and then treated with an excess of aqueous sulfuric acid. Theaqueous layer was extracted'with ether and the ether 32 299 nslz iaills$98.?

C F201 1 0-00 F1-C m-cooH 3. hviii .1 boilin 'pointbf 60 C./ 21'nm.- Hg.

The effect of this acid on the surface tension of water was determinedin the manner described in Example 4.

Concentration of Acid Surface Tension in Water (Wt. (Dynes/cm.) 0 73.00.33 40.1 1 0.67 37.2 1.10 33.4

10 C. was noticed. Vinylidene fluoride was bubbled through the resultingsuspension for 1 hour during which period 32 grams of bromine was addeddropwise. The solution was stirred for another hour, then the solutionfiltered, and the filtrate distilled at atmospheric pressure. Fifty-twograms of a product (boiling point 84-86 C.) was obtained which wasanalyzed by vapor phase chromatographic analysis and shown to be amixture of 49 grams C F,OCF CH,Br and 3 grams BrCF CH Br. The pureproduct was separated from the dibromide by another distillation.

in a similar manner fluorinated ethers were prepared in Z-methylsulfolane, butyrolaetone, and dimethyl formamide.

This compound had a boiling point of l40l42 C. and a refractive index ofl.3l85/24 C.

EXAMPLE l Perfluoroctanoic acid fluoride was prepared by reacting thecorresponding acid chloride with potassium fluoride in acetonitrile.Forty-two grams of the acid fluoride was added over a l-hour period to areaction mixture containing grams of cesium fluoride and 250 cc. ofacetonitrile. Sixteen and one-half grams of cyclohexane was added to thereaction mixture following which a solution of 32 grams of iodinemonochloride dissolved in acetonitrile was added dropwise over a 2-Solvont Ketono Fluoride Olefin Halogen Product and yield CH; O CsF Oli0H: Bra CaF1OCHzCHzBr g Yield: 14% C F3- C F:

CHa-CHg O KF CH2=HC1 Bra C F OCHzCHzBt g Yield: 4% /O C Fs- C Fa Hz-C=OO CSF CF2=CH1 Brz C3F7OCFzCHaBt -N0z Yield: 74%

CHa-C-C Fa (CH3)zNC=O O KF CFH=CH2 Brg C3F1OCFHCHzBr JLL Yield: 10% H CF3- 0 F3 EXAMPLE 9 hour fliiafiffifefifi'r'i'ifig overnight, thereaction mix- The compound 2 triflumomethy1 3 ture was poured into coldwater. The lower layer was perfluoropentanone was prepared in accordancewith the method of Smith et a]. (Journal of the American ChemicalSociety, 1962, Vol. 84, page 4285), by reacting perfluoropropylene withperfluoropropionyl fluoride in acetonitrile using cesium fluoride as acatalyst. Thirty-one grams of cesium fluoride and 200 ml. ofacetonitrile were admixed in a flask equipped with a dry ice condenserand 26 grams of 2-trifluoromethyl-3- perfluoropentanone was added over al-hour period. Thirty-two grams of bromine was then added dropwise overa 6-hour period while simultaneously bubbling vinylidene fluoridethrough the reaction mixture.

The reaction mixture was poured into 1 liter of ice water. The lowerlayer was collected and washed with water. Two immiscible liquids wereobtained, the lighter of which was distilled to give 10 grams of thecompound C F1 0 Fro F-CFO-CFzCHaBr separated and washed with water andthen dilute ammonia. The resulting material was distilled leaving 2grams of solid material in the distillation flask. The solid materialwas analyzed by infrared and nuclear magnetic resonance spectralanalysis and found to be the compound CaF11 It will be apparent thatmany modifications and variations may be effected without departing fromthe scope of the novel concepts of the present invention, and the

